• Title/Summary/Keyword: King Sejong Station

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An Experimental Study of the King Sejong Station and Siberian Frozen Soils (세종기지 및 시베리아 흙의 동결특성 시험)

  • Kim, Youngchin;Shin, Jaewon;Son, Seungmo
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.2
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    • pp.5-12
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    • 2009
  • Soil samples from the King Sejong Station in Antarctic and Vladivostok were tested in the laboratory and specific gravity, compaction curve, grain size distribution were determined. The effect of temperature change on the thermal conductivity, unfrozen water content, compressive strength were investigated. In addition, the change of tensile strength with temperature of the soil from Vladivostok was measured. Samples for the compressive strength test and tensional strength test were prepared in a mould with a fixed volume to prevent swelling. Also the effects of temperature and water content change on those strength were compared. Results from the thermal conductivity test showed that thermal conductivity values for both soils was larger at temperatures below freezing than those above freezing. The unfrozen water content dropped rapidly within a temperature range of $0{\sim}-5^{\circ}C$ and then gradually decreased further $-20^{\circ}C$. Compressive strength test results showed various stress/deformation curves with a change in water content. Sandy soil of the King Sejong Station had a much larger strength than ice at an identical temperature, while clayey soil of Vladivostok had a smaller strength than ice in the initial stage, but showed a larger strength at temperatures belows $-15^{\circ}C$. Tensile strength tests revealed an increase in the strength with a decreasing temperature.

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Surface Flux Measurements at King Sejong Station in West Antarctica: II. Turbulent exchanges of sensible heat and latent heat in the austral summer of 2002-2003 (남극 세종기지에서의 지표 플럭스 관측: II. 2002-2003년 남반구 여름 기간의 열과 수증기의 난류 교환)

  • Choi, Tae-Jin;Lee, Bang-Yong;Lee, Hee-Choon;Kim, Seong-Joong;Hong, Sung-Min
    • Journal of the Korean Geophysical Society
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    • v.8 no.3
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    • pp.159-167
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    • 2005
  • Turbulent fluxes of sensible heat and latent heat were analyzed at King Sejong station in the austral summer of 2002 (December) and 2003 (January and February). Monthly mean air temperatures of January and February (2.2oC) were similar to those averaged over 1988 to 2001. Precipitation was less in January and greater in February than those averaged over last 14 years. In December of 2002 and January, there was precipitation primarily when easterly wind blew usually. The frequency of snowfall was equal to or larger than that of rainfall. In the mean while, precipitation primarily in forms of rainfall occurred with westerly wind in February. In addition, while for easterly wind, temperature and humidity was low, temperature and humidity were high in case of westerly wind. Based on flux footprint, measured flux mainly came from within 300 m with maximum of 40 m upwind, indicating the insignificant role of the sea around the study site. Half-hourly downward short wave radiation amounted up to ∼ 1000 Wm-2 and net radiation ranged from -50 to 600 Wm-2. Half-hourly sensible heat flux was positive at daytime with maximum of ∼ 400 Wm-2, except the 27th and 28th in February of 2003 when it was negative all day despite of positive net radiation at short daytime. Latent heat flux was positive with maximum of ∼ 130 Wm-2. Depending on wind direction, the partitioning of net radiation into the sum of sensible heat flux and latent heat flux was larger than 0.8, indicating the strong source of the land surface for the atmospheric heating. The daytime averaged Bowen ratio (=sensible heat flux /latent heat flux) was significantly greater than 1, indicating that sensible heat flux was the main source to heat the atmosphere over the site.

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Estimation of R-value and Uniaxial Compressive Strength of Rocks around the King Sejong Station, Barton Peninsula, Antarctica from SilverSchmidt Q-value (실버슈미트 Q값으로부터 남극 바톤반도 세종과학기지 주변 암석의 R값 및 일축압축강도 추정)

  • Lim, Hyoun-Soo;Jang, Bo-An;Kim, Jung-Han;Kang, Seong-Seung
    • Tunnel and Underground Space
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    • v.25 no.2
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    • pp.199-209
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    • 2015
  • The rebound hardness test using the SilverSchmidt hammer was performed for diorite, granodiorite, and andesite exposed around the King Sejong Station, Barton peninsula. Then, the R-value and uniaxial compressive strength (UCS) of these rocks were estimated from the Q-values which were obtained from the SilverSchmidt hammer. The Q-value of diorite was distributed in the range from 67.0 to 89.5, granodiorite of the range from 57.5 to 89.0, and andesite of the range from 58.0 to 76.5. The average Q-values of diorite, granodiorite, and andesite were 76.0, 72.0, and 67.0, respectively. The converted UCS of diorite was distributed in the range from 118 to 195 MPa, granodiorite of the range from 91 to 193 MPa, and andesite of the range from 92 to 148 MPa. The average UCS of diorite, granodiorite, and andesite were 147, 136, and 117 MPa, respectively. The converted R-value of diorite was distributed in the range from 53.0 to 72.2, granodiorite of the range from 45.4 to 71.8, and andesite of the range from 45.8 to 60.9. The average Q-values of diorite, granodiorite, and andesite were 60.0, 58.0, and 53.0, respectively. The R-value was represented approximately 20% lower than the Q-value. In conclusion, it will be possibile that the R-value and UCS of rocks under the extreme area from the SilverSchmidt Q-value are evaluated.

Comparison between Total Least Squares and Ordinary Least Squares for Linear Relationship of Stable Water Isotopes (완전최소자승법과 보통최소자승법을 이용한 물안정동위원소의 선형관계식 비교)

  • Lee, Jeonghoon;Choi, Hye-Bin;Lee, Won Sang;Lee, Seung-Gu
    • Economic and Environmental Geology
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    • v.50 no.6
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    • pp.517-523
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    • 2017
  • A linear relationship between two stable water isotopes, oxygen and hydrogen, has been used to understand the water cycle as a basic tool. A slope and intercept from the linear relationship indicates what kind of physical processes occur during movement of water. Traditionally, ordinary least squares (OLS) method has been utilized for the linear relationship, but total least squares (TLS) method provides more accurate slope and intercept theoretically because isotopic compositions of both oxygen and hydrogen have uncertainties. In this work, OLS and TLS were compared with isotopic compositions of snow and snowmelt collected from the King Sejong Station, Antarctica and isotopic compositions of water vapor observed by Lee et al. (2013) in the western part of Korea. The slopes from the linear relationship of isotopic compositions of snow and snowmelt at the King Sejong Station were estimated to be 7.00 (OLS) and 7.16(TLS) and the slopes of stable water vapor isotopes were 7.75(OLS) and 7.87(TLS). There was a melting process in the snow near the King Sejong Station and the water vapor was directly transported from the ocean to the study area based on the slope calculations. There is no significant difference in two slopes to interpret the physical processes. However, it is necessary to evaluate the slope differences from the two methods for studies for example, groundwater recharge processes, using the absolute slope values.

Physico-chemical Characteristics of Soil in the Vicinity of King Sejong Station, King George Island, Antarctica (남극 킹조지섬 세종기지 주변지역 토양의 물리화학적 특성)

  • Choi, Ik-Won;Park, Yang-Ju;Seo, Dong-Cheol;Kang, Se-Won;Jeon, Weon-Tai;Kang, Ui-Gum;Sung, Hwan-Hoo;Hur, Tai-Young;Heo, Jong-Soo;Cho, Ju-Sik
    • Korean Journal of Soil Science and Fertilizer
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    • v.44 no.5
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    • pp.709-716
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    • 2011
  • In order to collect basic data of soil environment in the Vicinity of King Sejong Station, King George Island, Antarctica, the physico-chemical characteristics of soils were investigated. Soil samples were collected in Barton Peninsula from 13 sites according to direction from the Sejong Cape. Soils from 13 sites were divided into three groups. The sand percentage of soils were much higher as above 90% than silt and clay percentages of soils at the all sites. Soil texture was classified sandy (10 sites) and loamy sand (3 sites). In distribution characteristics at different soil particles according to direction, large particles ($>500{\mu}m$) were higher in the order of Group 1 (Marian cove coast regions) > Group 2 (Inland regions) > Group 3 (Maxwell bay coast regions). On the other hand, small particles ($<355{\mu}m$) were higher in the order of Group 3 > Group 2 > Group 1. Chemical characteristic of soils showed significant differences at different areas. pH ranged 4.5-6.7, showing it was slightly acid and EC ranged $0.06-0.16dS\;m^{-1}$. T-N, OM and T-C contents were high at #6, #8, #12 and #13 sites. T-P and P2O5 contents were high at #9 and #12 sites. The results of this study will be helpful to understand soil environment in the Antarctic Peninsula and surrounding islands.